1. Field of the Invention
The present invention relates to a sputtering system, and more particularly, to a magnetron sputtering system using electromagnets.
2. Discussion of the Related Art
Generally, sputtering is a technique for forming a metal thin film and an insulating film on a substrate, wherein physical deposition processes are used rather than vacuum deposition processes. In addition, different sputtering techniques include diode DC sputtering, triode sputtering, and magnetron sputtering.
FIG. 1 illustrates a magnetron sputtering system according to the prior art. In FIG. 1, the sputtering system includes load locks 101 and 102, a heater chamber 103, processing chambers 104, 105, and 106, and a transfer chamber 107. The load locks 101 and 102 attenuate any pressure differential prior to introducing a substrate into the processing chambers 104, 105, and 106 where deposition is performed. The heater chamber 103 performs pre-heating of the substrate prior to the introduction into the processing chambers 104, 105, and 106. The processing chambers 104, 105, and 106 include various driving units and a target for material deposition. The transfer chamber 107 includes a vacuum processing robot for transferring each substrate between each of the individual processing chambers 104, 105, and 106, a well as between the load locks 101 and 102 and the processing chambers 104, 105, and 106.
FIG. 2 illustrates an inner structure of one of the process chambers according to the prior art. In general, sputtering processes are performed within a vacuum chamber filled with Argon gas. The process chamber includes a target 201 having a straight-line plate shaped section comprising deposition materials, a fixed plate 202 for fixing the target 201, and a magnet 203 located at a rear side of the fixed plate 202 for forming an electric field in the target 201. The electric field generated by the magnet 203 confines electrons emitted from the target 201, thereby forming a plasma region around the target 201. A platen 204 is located at a bottom side of the chamber for modulating an interval from the target 201 during deposition processing of a film.
In a magnetron sputtering system, a cathode electrode is generally connected to a target. Then, a positive potential is applied to a substrate of a deposition object, so that an electron is emitted from the target toward the substrate. The emitted electron and Argon gas injected into the chamber react with each other to ionize the Argon gas, thereby forming a plasma region around the target. Accordingly, the highly energized Argon ion located within the plasma region collides with the target, thereby detaching material of the target. Then, the detached material is deposited onto the substrate.
FIG. 3 is a perspective view showing a magnet chamber according to the prior art.
In FIG. 3, a magnet 203 controls a flow of electrons, and scans to form a plasma by moving left and right. Alternatively, the magnet 203 may also scan to form a plasma by moving up and down. A ball shaft 206 is formed at a predetermined portion at a lateral side of the magnet 203 to transmit a driving force to maintain scanning of the magnet 203. A motor (not shown) is connected to a front end of the ball shaft 206. Since the ball shaft 206 is the weakest part of the magnet driving unit, structural improvements of the ball shaft 202 are required. In addition, a linear motion guide 207 is provided in a perpendicular direction to the magnet 203, and strengthens lateral side forces applied to the magnet 203 and the ball shaft 206.
However, the related art magnetron sputtering system has the following problems. First, a plasma that is generated will be inclined towards a specific region because of the magnetic field that is produced by a large sized magnet, thereby causing deposition of a thin film having a non-uniform thickness. In addition, once a first thin film is deposited having a non-uniform thickness, it is impossible to deposit any additional thin films, thereby lowering yield. FIG. 4 is a diagram demonstrating differences in thin film thickness across a surface of a substrate when using a sputtering system according to the prior art. In FIG. 4, black parts have a thickness that are larger than a thickness of the white parts. Second, since the magnetic is mechanically driven by a motor, and the ball shaft has a maximum operational speed, the deposition speed of the sputtering system according to the prior art is limited. Third, when driving the magnet during the deposition process, significant vibration is generated and is transmitted to the entire sputtering system, thereby negatively influencing durability of individual components of the sputtering system.